Kenny Jackett's not satisfied how Tom Naylor and Bryn Morris have looked as a pair so far and instead looking for a fresh face.
Work’s presently going on behind the scenes to find that player as Pompey look to finally light the touchpaper to their campaign.
The Blues were linked with ex-Aston Villa man Jake Doyle-Hayes earlier this week.
But we’ve taken a look at some of the other engine-room operators who could potentially fit the bill...
1. Kiernan Dewsbury-Hall - Leicester
The 22-year-old had an excellent spell at Blackpool during the second half of last term, scoring four goals in 10 games. A left-footer, which could appeal as Pompey don't have anyone in the middle with that attribute.
Photo: Charlotte Tattersall
2. John Buckley - Blackburn Rovers
The 20-year-old scored two goals in 23 appearances for Rovers last season. Manager Tony Mowbray admitted earlier in the window that Buckley would benefit from playing 40 games in League One and two clubs had made enquiries, but was staying at Ewood Park for the meantime. However, he's only made two outings off the bench so far and his situation could change ahead of the deadline.
Photo: Julian Finney
3. Conor Coventry - West Ham United
The Republic of Ireland youth international was enjoying himself on loan at Lincoln last term before the lockdown period. The 20-year-old was then named on the bench on several occasions for West Ham after the Premier League restarted. Coventry scored a brilliant goal in the Hammers under-21s' 1-0 win over Colchester in the EFL Trophy on Tuesday and may be craving more senior football.
Photo: James Chance
4. Joe Morrell - Bristol City
Pompey have already raided the Robins once during the window by signing Cam Pring. Morrell had a fine season at Lincoln last term and was awarded their Player of the Year. However, he's been left out of their opening six match-day squads this campaign - despite being an estasblished starter for Wales.
Photo: Stu Forster